1. Field of the Invention
The present invention relates to communications systems, and particularly to a method and system for bridging voice communications.
2. Discussion of the Known Art
Many wireless voice radios and devices are unable to link with one another because of different network frequency allocations and transmission protocols, end usage, proprietary technology, and/or limitations of currently available connectivity solutions. The use of incompatible voice communication radios by first responders including fire, police and rescue personnel at an incident can cause serious problems if all responders and their lines of command are not frequently updated because of their inability to communicate with one another in real time.
A system known as First InterComm offered by BAE Systems enables responders whose radios operate on different frequencies and use different transmission protocols, to communicate with one another by using their existing radios and a separate module mounted in each responder's vehicle. When installed, the module operates to create a temporary digital mesh network that includes the vehicle in which it is mounted, and all other vehicles equipped with the module in the vicinity of the incident. Each module monitors both the mesh network and the radio channel normally used by the responder in whose vehicle the module is installed.
When a responder originates a voice message using his or her radio, the module detects the corresponding voice signal, converts it to a digital format, and relays the message digitally across the mesh network. The modules in the other responders' vehicles re-convert the digital message into an analog voice signal, and transmit the voice signal on the same RF channels and with the same modulation protocols used by each of the other responders' radios. The other responders can therefore hear the original voice message over their own radios with little if any time delay. See, U.S. Pat. No. 7,508,840 (Mar. 24, 2009), U.S. Pat. Application Pub. 2009/0174547 (Jul. 9, 2009), and U.S. Pat. Application Pub. 2009/0207852 (Aug. 20, 2009).
Notwithstanding the known art, a need continues for a system and technique for bridging voice communications among users of disparate voice communication radios that are located or may travel far away from one another, particularly during the course of military and tactical missions in potentially hostile environments.